The role of dendritic cell metabolism in antitumor immunity

• Autor(a) principal: Albuquerque, Cristiana Martins
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/30119
• topic: Plasmacytoid dendritic cells; Tumor microenvironment; Interferon; Cell metabolism; Metabolomics; Nuclear magnetic resonance spectroscopy

Plasmacytoid dendritic cells (pDCs) are characterized by their ability to produce large amounts of interferon type I (IFN-α/β) when TLR7/9 receptors are stimulated. In cancer, however, pDCs have been shown to decrease their response, decreasing interferon production and thus contributing to an immunosuppressive environment. In recent years, cellular metabolism has been shown to play a key role in the activation process of pDCs, although a comprehensive understanding of the relation between metabolic adaptations on these cells and their stimulatory or regulatory functions is still lacking. The present work aims to further clarify this relation. Firstly, the human CAL-1 pDC cell line was cultured in vitro and treated with a TLR7 agonist (CL307) at different concentrations and incubation times, in order to optimize conditions for CAL-1 activation. Then, the work focused on the phenotypic and metabolic responses of pDCs to CL307, under the influence of factors that mimic the tumor microenvironment (TNF-α+TGF-β). In addition to the evaluation of IFN-β and TNF-α mRNA expression levels, the polar fractions of the cells were analyzed by 1H-NMR spectroscopy and about 30 intracellular metabolites were identified. Culture media supernatants were further analyzed to characterize cell consumption and excretion patterns. The levels of IFN-β and TNF-α mRNA increased significantly upon incubation with CL307 1 µM for 3h. Exposure to the stimulus for 3h resulted in a greater change in IFN-β and TNF-α mRNA, but had a lower impact on cell composition and metabolic activity than an incubation of 1h. Metabolic changes associated with activation with CL307 resulted in intensification of glycolysis and the tricarboxylic acid (TCA) cycle, which may be correlated with the increased biosynthetic requirements inherent in an immunogenic profile. Under the influence of TNF-α and TGF-β, there was a suppression of IFN-β and TNF-α mRNA expression associated with activation, accompanied by attenuation of metabolic changes. Overall, this study demonstrated that, in the presence of a tumor microenvironment, CAL-1 plasmacytoid dendritic cells alter their phenotypic and metabolic response to TLR7 stimulation.